Conventional methods for dewatering and drying substances such as oils and fats include heating the substance, reducing the pressure around the substance, adding a desiccant to the substance, or a combination of these. However, the heating and the pressure reduction require much energy necessary for vaporizing water. In particular, the pressure reduction on an industrial scale further requires vacuum equipment which is expensive. For the addition of desiccant, a large amount of desiccant must be added, resulting in the formation of a water-absorbed desiccant residue that has at least the same volume as that of the water absorbed, which requires the post-treatment of such a large amount of wastes.
Where industrial products are produced from oil or fat (for example, where oil or fat is hydrolyzed to produce diglycerides, monoglycerides, fatty acids or glycerin), the starting oil or fat is often pre-purified in order to reduce the content of the impurities to be in the products. To remove water-soluble substances from raw oil or fat, the raw oil or fat may be washed with water. However, the washing produces a large amount of wastes that must be post-treated.
Heretofore, lipases have been used for hydrolysis, esterification and interesterification of oil or fat. However, there is no precedent for the case of using lipases for dewatering, for drying and even for purifying oil or fat.
One object of the present invention is to provide a simple process for reducing water in oil or fat and for purifying oil or fat. Another object of the present invention is to provide a process useful for obtaining hydrolysates of oil or fat.